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/* net/atm/clip.c - RFC1577 Classical IP over ATM */

/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */

#include <linux/config.h>

#include <linux/string.h>

#include <linux/errno.h>

#include <linux/kernel.h> /* for UINT_MAX */

#include <linux/module.h>

#include <linux/init.h>

#include <linux/netdevice.h>

#include <linux/skbuff.h>

#include <linux/wait.h>

#include <linux/timer.h>

#include <linux/if_arp.h> /* for some manifest constants */

#include <linux/notifier.h>

#include <linux/atm.h>

#include <linux/atmdev.h>

#include <linux/atmclip.h>

#include <linux/atmarp.h>

#include <linux/ip.h> /* for net/route.h */

#include <linux/in.h> /* for struct sockaddr_in */

#include <linux/if.h> /* for IFF_UP */

#include <linux/inetdevice.h>

#include <linux/bitops.h>

#include <net/route.h> /* for struct rtable and routing */

#include <net/icmp.h> /* icmp_send */

#include <asm/param.h> /* for HZ */

#include <asm/byteorder.h> /* for htons etc. */

#include <asm/system.h> /* save/restore_flags */

#include <asm/uaccess.h>

#include <asm/atomic.h>

#include "common.h"

#include "resources.h"

#include "ipcommon.h"

#include <net/atmclip.h>

#if 0

#define DPRINTK(format,args...) printk(format,##args)

#else

#define DPRINTK(format,args...)

#endif

struct net_device *clip_devs = NULL;

struct atm_vcc *atmarpd = NULL;

static struct neigh_table clip_tbl;

static struct timer_list idle_timer;

static int start_timer = 1;

static int to_atmarpd(enum atmarp_ctrl_type type,int itf,unsigned long ip)

{

        struct atmarp_ctrl *ctrl;

        struct sk_buff *skb;

        DPRINTK("to_atmarpd(%d)\n",type);

        if (!atmarpd) return -EUNATCH;

        skb = alloc_skb(sizeof(struct atmarp_ctrl),GFP_ATOMIC);

        if (!skb) return -ENOMEM;

        ctrl = (struct atmarp_ctrl *) skb_put(skb,sizeof(struct atmarp_ctrl));

        ctrl->type = type;

        ctrl->itf_num = itf;

        ctrl->ip = ip;

        atm_force_charge(atmarpd,skb->truesize);

        skb_queue_tail(&atmarpd->sk->receive_queue,skb);

        wake_up(&atmarpd->sleep);

        return 0;

}

static void link_vcc(struct clip_vcc *clip_vcc,struct atmarp_entry *entry)

{

        DPRINTK("link_vcc %p to entry %p (neigh %p)\n",clip_vcc,entry,

            entry->neigh);

        clip_vcc->entry = entry;

        clip_vcc->xoff = 0; /* @@@ may overrun buffer by one packet */

        clip_vcc->next = entry->vccs;

        entry->vccs = clip_vcc;

        entry->neigh->used = jiffies;

}

static void unlink_clip_vcc(struct clip_vcc *clip_vcc)

{

        struct atmarp_entry *entry = clip_vcc->entry;

        struct clip_vcc **walk;

        if (!entry) {

                printk(KERN_CRIT "!clip_vcc->entry (clip_vcc %p)\n",clip_vcc);

                return;

        }

        spin_lock_bh(&entry->neigh->dev->xmit_lock);    /* block clip_start_xmit() */

        entry->neigh->used = jiffies;

        for (walk = &entry->vccs; *walk; walk = &(*walk)->next)

                if (*walk == clip_vcc) {

                        int error;

                        *walk = clip_vcc->next; /* atomic */

                        clip_vcc->entry = NULL;

                        if (clip_vcc->xoff)

                                netif_wake_queue(entry->neigh->dev);

                        if (entry->vccs)

                                goto out;

                        entry->expires = jiffies-1;

                                /* force resolution or expiration */

                        error = neigh_update(entry->neigh,NULL,NUD_NONE,0,0);

                        if (error)

                                printk(KERN_CRIT "unlink_clip_vcc: "

                                    "neigh_update failed with %d\n",error);

                        goto out;

                }

        printk(KERN_CRIT "ATMARP: unlink_clip_vcc failed (entry %p, vcc "

          "0x%p)\n",entry,clip_vcc);

out:

        spin_unlock_bh(&entry->neigh->dev->xmit_lock);

}

static void idle_timer_check(unsigned long dummy)

{

        int i;

        /*DPRINTK("idle_timer_check\n");*/

        write_lock(&clip_tbl.lock);

        for (i = 0; i <= NEIGH_HASHMASK; i++) {

                struct neighbour **np;

                for (np = &clip_tbl.hash_buckets[i]; *np;) {

                        struct neighbour *n = *np;

                        struct atmarp_entry *entry = NEIGH2ENTRY(n);

                        struct clip_vcc *clip_vcc;

                        write_lock(&n->lock);

                        for (clip_vcc = entry->vccs; clip_vcc;

                            clip_vcc = clip_vcc->next)

                                if (clip_vcc->idle_timeout &&

                                    time_after(jiffies, clip_vcc->last_use+

                                    clip_vcc->idle_timeout)) {

                                        DPRINTK("releasing vcc %p->%p of "

                                            "entry %p\n",clip_vcc,clip_vcc->vcc,

                                            entry);

                                        vcc_release_async(clip_vcc->vcc,

                                                          -ETIMEDOUT);

                                }

                        if (entry->vccs ||

                            time_before(jiffies, entry->expires)) {

                                np = &n->next;

                                write_unlock(&n->lock);

                                continue;

                        }

                        if (atomic_read(&n->refcnt) > 1) {

                                struct sk_buff *skb;

                                DPRINTK("destruction postponed with ref %d\n",

                                    atomic_read(&n->refcnt));

                                while ((skb = skb_dequeue(&n->arp_queue)) !=

                                     NULL)

                                        dev_kfree_skb(skb);

                                np = &n->next;

                                write_unlock(&n->lock);

                                continue;

                        }

                        *np = n->next;

                        DPRINTK("expired neigh %p\n",n);

                        n->dead = 1;

                        write_unlock(&n->lock);

                        neigh_release(n);

                }

        }

        mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);

        write_unlock(&clip_tbl.lock);

}

static int clip_arp_rcv(struct sk_buff *skb)

{

        struct atm_vcc *vcc;

        DPRINTK("clip_arp_rcv\n");

        vcc = ATM_SKB(skb)->vcc;

        if (!vcc || !atm_charge(vcc,skb->truesize)) {

                dev_kfree_skb_any(skb);

                return 0;

        }

        DPRINTK("pushing to %p\n",vcc);

        DPRINTK("using %p\n",CLIP_VCC(vcc)->old_push);

        CLIP_VCC(vcc)->old_push(vcc,skb);

        return 0;

}

static void clip_push(struct atm_vcc *vcc,struct sk_buff *skb)

{

        struct clip_vcc *clip_vcc = CLIP_VCC(vcc);

        DPRINTK("clip push\n");

        if (!skb) {

                DPRINTK("removing VCC %p\n",clip_vcc);

                if (clip_vcc->entry) unlink_clip_vcc(clip_vcc);

                clip_vcc->old_push(vcc,NULL); /* pass on the bad news */

                kfree(clip_vcc);

                return;

        }

        atm_return(vcc,skb->truesize);

        skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs;

                /* clip_vcc->entry == NULL if we don't have an IP address yet */

        if (!skb->dev) {

                dev_kfree_skb_any(skb);

                return;

        }

        ATM_SKB(skb)->vcc = vcc;

        skb->mac.raw = skb->data;

        if (!clip_vcc->encap || skb->len < RFC1483LLC_LEN || memcmp(skb->data,

            llc_oui,sizeof(llc_oui))) skb->protocol = htons(ETH_P_IP);

        else {

                skb->protocol = ((u16 *) skb->data)[3];

                skb_pull(skb,RFC1483LLC_LEN);

                if (skb->protocol == htons(ETH_P_ARP)) {

                        PRIV(skb->dev)->stats.rx_packets++;

                        PRIV(skb->dev)->stats.rx_bytes += skb->len;

                        clip_arp_rcv(skb);

                        return;

                }

        }

        clip_vcc->last_use = jiffies;

        PRIV(skb->dev)->stats.rx_packets++;

        PRIV(skb->dev)->stats.rx_bytes += skb->len;

        memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));

        netif_rx(skb);

}

/*

 * Note: these spinlocks _must_not_ block on non-SMP. The only goal is that

 * clip_pop is atomic with respect to the critical section in clip_start_xmit.

 */

static void clip_pop(struct atm_vcc *vcc,struct sk_buff *skb)

{

        struct clip_vcc *clip_vcc = CLIP_VCC(vcc);

        struct net_device *dev = skb->dev;

        int old;

        unsigned long flags;

        DPRINTK("clip_pop(vcc %p)\n",vcc);

        clip_vcc->old_pop(vcc,skb);

        /* skb->dev == NULL in outbound ARP packets */

        if (!dev) return;

        spin_lock_irqsave(&PRIV(dev)->xoff_lock,flags);

        if (atm_may_send(vcc,0)) {

                old = xchg(&clip_vcc->xoff,0);

                if (old) netif_wake_queue(dev);

        }

        spin_unlock_irqrestore(&PRIV(dev)->xoff_lock,flags);

}

static void clip_neigh_destroy(struct neighbour *neigh)

{

        DPRINTK("clip_neigh_destroy (neigh %p)\n",neigh);

        if (NEIGH2ENTRY(neigh)->vccs)

                printk(KERN_CRIT "clip_neigh_destroy: vccs != NULL !!!\n");

        NEIGH2ENTRY(neigh)->vccs = (void *) 0xdeadbeef;

}

static void clip_neigh_solicit(struct neighbour *neigh,struct sk_buff *skb)

{

        DPRINTK("clip_neigh_solicit (neigh %p, skb %p)\n",neigh,skb);

        to_atmarpd(act_need,PRIV(neigh->dev)->number,NEIGH2ENTRY(neigh)->ip);

}

static void clip_neigh_error(struct neighbour *neigh,struct sk_buff *skb)

{

#ifndef CONFIG_ATM_CLIP_NO_ICMP

        icmp_send(skb,ICMP_DEST_UNREACH,ICMP_HOST_UNREACH,0);

#endif

        kfree_skb(skb);

}

static struct neigh_ops clip_neigh_ops = {

        family:                 AF_INET,

        destructor:             clip_neigh_destroy,

        solicit:                clip_neigh_solicit,

        error_report:           clip_neigh_error,

        output:                 dev_queue_xmit,

        connected_output:       dev_queue_xmit,

        hh_output:              dev_queue_xmit,

        queue_xmit:             dev_queue_xmit,

};

static int clip_constructor(struct neighbour *neigh)

{

        struct atmarp_entry *entry = NEIGH2ENTRY(neigh);

        struct net_device *dev = neigh->dev;

        struct in_device *in_dev = dev->ip_ptr;

        DPRINTK("clip_constructor (neigh %p, entry %p)\n",neigh,entry);

        if (!in_dev) return -EINVAL;

        neigh->type = inet_addr_type(entry->ip);

        if (neigh->type != RTN_UNICAST) return -EINVAL;

        if (in_dev->arp_parms) neigh->parms = in_dev->arp_parms;

        neigh->ops = &clip_neigh_ops;

        neigh->output = neigh->nud_state & NUD_VALID ?

            neigh->ops->connected_output : neigh->ops->output;

        entry->neigh = neigh;

        entry->vccs = NULL;

        entry->expires = jiffies-1;

        return 0;

}

static u32 clip_hash(const void *pkey, const struct net_device *dev)

{

        u32 hash_val;

        hash_val = *(u32*)pkey;

        hash_val ^= (hash_val>>16);

        hash_val ^= hash_val>>8;

        hash_val ^= hash_val>>3;

        hash_val = (hash_val^dev->ifindex)&NEIGH_HASHMASK;

        return hash_val;

}

static struct neigh_table clip_tbl = {

        NULL,                   /* next */

        AF_INET,                /* family */

        sizeof(struct neighbour)+sizeof(struct atmarp_entry), /* entry_size */

        4,                      /* key_len */

        clip_hash,

        clip_constructor,       /* constructor */

        NULL,                   /* pconstructor */

        NULL,                   /* pdestructor */

        NULL,                   /* proxy_redo */

        "clip_arp_cache",

        {                       /* neigh_parms */

                NULL,           /* next */

                NULL,           /* neigh_setup */

                &clip_tbl,      /* tbl */

                0,               /* entries */

                NULL,           /* priv */

                NULL,           /* sysctl_table */

                30*HZ,          /* base_reachable_time */

                1*HZ,           /* retrans_time */

                60*HZ,          /* gc_staletime */

                30*HZ,          /* reachable_time */

                5*HZ,           /* delay_probe_time */

                3,              /* queue_len */

                3,              /* ucast_probes */

                0,               /* app_probes */

                3,              /* mcast_probes */

                1*HZ,           /* anycast_delay */

                (8*HZ)/10,      /* proxy_delay */

                1*HZ,           /* proxy_qlen */

                64              /* locktime */

        },

        30*HZ,128,512,1024      /* copied from ARP ... */

};

/* @@@ copy bh locking from arp.c -- need to bh-enable atm code before */

/*

 * We play with the resolve flag: 0 and 1 have the usual meaning, but -1 means

 * to allocate the neighbour entry but not to ask atmarpd for resolution. Also,

 * don't increment the usage count. This is used to create entries in

 * clip_setentry.

 */

static int clip_encap(struct atm_vcc *vcc,int mode)

{

        CLIP_VCC(vcc)->encap = mode;

        return 0;

}

static int clip_start_xmit(struct sk_buff *skb,struct net_device *dev)

{

        struct clip_priv *clip_priv = PRIV(dev);

        struct atmarp_entry *entry;

        struct atm_vcc *vcc;

        int old;

        unsigned long flags;

        DPRINTK("clip_start_xmit (skb %p)\n",skb);

        if (!skb->dst) {

                printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");

                dev_kfree_skb(skb);

                clip_priv->stats.tx_dropped++;

                return 0;

        }

        if (!skb->dst->neighbour) {

#if 0

                skb->dst->neighbour = clip_find_neighbour(skb->dst,1);

                if (!skb->dst->neighbour) {

                        dev_kfree_skb(skb); /* lost that one */

                        clip_priv->stats.tx_dropped++;

                        return 0;

                }

#endif

                printk(KERN_ERR "clip_start_xmit: NO NEIGHBOUR !\n");

                dev_kfree_skb(skb);

                clip_priv->stats.tx_dropped++;

                return 0;

        }

        entry = NEIGH2ENTRY(skb->dst->neighbour);

        if (!entry->vccs) {

                if (time_after(jiffies, entry->expires)) {

                        /* should be resolved */

                        entry->expires = jiffies+ATMARP_RETRY_DELAY*HZ;

                        to_atmarpd(act_need,PRIV(dev)->number,entry->ip);

                }

                if (entry->neigh->arp_queue.qlen < ATMARP_MAX_UNRES_PACKETS)

                        skb_queue_tail(&entry->neigh->arp_queue,skb);

                else {

                        dev_kfree_skb(skb);

                        clip_priv->stats.tx_dropped++;

                }

                return 0;

        }

        DPRINTK("neigh %p, vccs %p\n",entry,entry->vccs);

        ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;

        DPRINTK("using neighbour %p, vcc %p\n",skb->dst->neighbour,vcc);

        if (entry->vccs->encap) {

                void *here;

                here = skb_push(skb,RFC1483LLC_LEN);

                memcpy(here,llc_oui,sizeof(llc_oui));

                ((u16 *) here)[3] = skb->protocol;

        }

        atomic_add(skb->truesize,&vcc->sk->wmem_alloc);

        ATM_SKB(skb)->atm_options = vcc->atm_options;

        entry->vccs->last_use = jiffies;

        DPRINTK("atm_skb(%p)->vcc(%p)->dev(%p)\n",skb,vcc,vcc->dev);

        old = xchg(&entry->vccs->xoff,1); /* assume XOFF ... */

        if (old) {

                printk(KERN_WARNING "clip_start_xmit: XOFF->XOFF transition\n");

                return 0;

        }

        clip_priv->stats.tx_packets++;

        clip_priv->stats.tx_bytes += skb->len;

        (void) vcc->send(vcc,skb);

        if (atm_may_send(vcc,0)) {

                entry->vccs->xoff = 0;

                return 0;

        }

        spin_lock_irqsave(&clip_priv->xoff_lock,flags);

        netif_stop_queue(dev); /* XOFF -> throttle immediately */

        barrier();

        if (!entry->vccs->xoff)

                netif_start_queue(dev);

                /* Oh, we just raced with clip_pop. netif_start_queue should be

                   good enough, because nothing should really be asleep because

                   of the brief netif_stop_queue. If this isn't true or if it

                   changes, use netif_wake_queue instead. */

        spin_unlock_irqrestore(&clip_priv->xoff_lock,flags);

        return 0;

}

static struct net_device_stats *clip_get_stats(struct net_device *dev)

{

        return &PRIV(dev)->stats;

}

static int clip_mkip(struct atm_vcc *vcc,int timeout)

{

        struct clip_vcc *clip_vcc;

        struct sk_buff_head copy;

        struct sk_buff *skb;

        if (!vcc->push) return -EBADFD;

        clip_vcc = kmalloc(sizeof(struct clip_vcc),GFP_KERNEL);

        if (!clip_vcc) return -ENOMEM;

        DPRINTK("mkip clip_vcc %p vcc %p\n",clip_vcc,vcc);

        clip_vcc->vcc = vcc;

        vcc->user_back = clip_vcc;

        clip_vcc->entry = NULL;

        clip_vcc->xoff = 0;

        clip_vcc->encap = 1;

        clip_vcc->last_use = jiffies;

        clip_vcc->idle_timeout = timeout*HZ;

        clip_vcc->old_push = vcc->push;

        clip_vcc->old_pop = vcc->pop;

        vcc->push = clip_push;

        vcc->pop = clip_pop;

        skb_queue_head_init(&copy);

        skb_migrate(&vcc->sk->receive_queue,&copy);

        /* re-process everything received between connection setup and MKIP */

        while ((skb = skb_dequeue(&copy)))

                if (!clip_devs) {

                        atm_return(vcc,skb->truesize);

                        kfree_skb(skb);

                }

                else {

                        unsigned int len = skb->len;

                        clip_push(vcc,skb);

                        PRIV(skb->dev)->stats.rx_packets--;

                        PRIV(skb->dev)->stats.rx_bytes -= len;

                }

        return 0;

}

static int clip_setentry(struct atm_vcc *vcc,u32 ip)

{

        struct neighbour *neigh;

        struct atmarp_entry *entry;

        int error;

        struct clip_vcc *clip_vcc;

        struct rtable *rt;

        if (vcc->push != clip_push) {

                printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");

                return -EBADF;

        }

        clip_vcc = CLIP_VCC(vcc);

        if (!ip) {

                if (!clip_vcc->entry) {

                        printk(KERN_ERR "hiding hidden ATMARP entry\n");

                        return 0;

                }

                DPRINTK("setentry: remove\n");

                unlink_clip_vcc(clip_vcc);

                return 0;

        }

        error = ip_route_output(&rt,ip,0,1,0);

        if (error) return error;

        neigh = __neigh_lookup(&clip_tbl,&ip,rt->u.dst.dev,1);

        ip_rt_put(rt);

        if (!neigh)

                return -ENOMEM;

        entry = NEIGH2ENTRY(neigh);

        if (entry != clip_vcc->entry) {

                if (!clip_vcc->entry) DPRINTK("setentry: add\n");

                else {

                        DPRINTK("setentry: update\n");

                        unlink_clip_vcc(clip_vcc);

                }

                link_vcc(clip_vcc,entry);

        }

        error = neigh_update(neigh,llc_oui,NUD_PERMANENT,1,0);

        neigh_release(neigh);

        return error;

}

static int clip_init(struct net_device *dev)

{

        DPRINTK("clip_init %s\n",dev->name);

        dev->hard_start_xmit = clip_start_xmit;

        /* sg_xmit ... */

        dev->hard_header = NULL;

        dev->rebuild_header = NULL;

        dev->set_mac_address = NULL;

        dev->hard_header_parse = NULL;

        dev->hard_header_cache = NULL;

        dev->header_cache_update = NULL;

        dev->change_mtu = NULL;

        dev->do_ioctl = NULL;

        dev->get_stats = clip_get_stats;

        dev->type = ARPHRD_ATM;

        dev->hard_header_len = RFC1483LLC_LEN;

        dev->mtu = RFC1626_MTU;

        dev->addr_len = 0;

        dev->tx_queue_len = 100; /* "normal" queue (packets) */

            /* When using a "real" qdisc, the qdisc determines the queue */

            /* length. tx_queue_len is only used for the default case, */

            /* without any more elaborate queuing. 100 is a reasonable */

            /* compromise between decent burst-tolerance and protection */

            /* against memory hogs. */

        dev->flags = 0;

        return 0;

}

static int clip_create(int number)

{

        struct net_device *dev;

        struct clip_priv *clip_priv;

        int error;

        if (number != -1) {

                for (dev = clip_devs; dev; dev = PRIV(dev)->next)

                        if (PRIV(dev)->number == number) return -EEXIST;

        }

        else {

                number = 0;

                for (dev = clip_devs; dev; dev = PRIV(dev)->next)

                        if (PRIV(dev)->number >= number)

                                number = PRIV(dev)->number+1;

        }

        dev = kmalloc(sizeof(struct net_device)+sizeof(struct clip_priv),

            GFP_KERNEL);

        if (!dev) return -ENOMEM;

        memset(dev,0,sizeof(struct net_device)+sizeof(struct clip_priv));

        clip_priv = PRIV(dev);

        sprintf(dev->name,"atm%d",number);

        dev->init = clip_init;

        spin_lock_init(&clip_priv->xoff_lock);

        clip_priv->number = number;

        error = register_netdev(dev);

        if (error) {

                kfree(dev);

                return error;

        }

        clip_priv->next = clip_devs;

        clip_devs = dev;

        DPRINTK("registered (net:%s)\n",dev->name);

        return number;

}

static int clip_device_event(struct notifier_block *this,unsigned long event,

    void *dev)